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Joseph Myers e4e52ff059 Improve float range reduction accuracy near pi/2 (bug 21094).
Bug 21094 reports 3ulp errors of cosf and tanf for certain arguments
near pi/2 arising from the use of an insufficiently accurate range
reduction.  (To be clear, this is a quality-of-implementation issue
relating to the apparent intent of those particular cosf and tanf
implementations; 3ulp is within the general glibc accuracy goals, so
not inherently a bug.)

This patch fixes that error by making a wider range of cases use the
existing more accurate range reduction for arguments close to pi/2.
The wider range of values is still narrow enough for the "z -=
pio2_2;" in the more accurate case to be exact, as the code expects.

Tested for x86_64, x86 and mips64; no ulps updates needed (but at
least on mips64, the larger ulps were seen if the tests were added
without the substantive fix).

	[BZ #21094]
	* sysdeps/ieee754/flt-32/e_rem_pio2f.c (__ieee754_rem_pio2f): Use
	24+24+24-bit pi for wider range of values around pi/2.
	* math/auto-libm-test-in: Add more tests of cos and tan.
	* math/auto-libm-test-out-cos: Regenerated.
	* math/auto-libm-test-out-tan: Likewise.
2017-03-15 22:00:54 +00:00
argp
assert
benchtests
bits Refer to <signal.h> instead of <pthread.h> in <bits/sigthread.h> 2017-02-28 10:34:15 +01:00
catgets
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crypt
csu
ctype
debug Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
dirent
dlfcn Miscellaneous low-risk changes preparing for _ISOMAC testsuite. 2017-03-01 20:32:50 -05:00
elf Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
gmon
gnulib
grp
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iconv Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
iconvdata Document and fix --enable-bind-now [BZ #21015] 2017-03-02 14:44:28 +01:00
include Split helper classification macros from mathcalls.h 2017-03-15 09:39:16 -03:00
inet Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
intl Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
io Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
libidn
libio Clean up conditionals for declaration of gets. 2017-02-25 09:47:51 -05:00
locale Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
localedata Bug 20313: Update to Unicode 9.0.0 2017-02-21 06:30:38 -05:00
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malloc Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
manual timezone: Remove TZNAME_MAX limit from sysconf [BZ #15576] 2017-03-07 17:45:38 +01:00
math Improve float range reduction accuracy near pi/2 (bug 21094). 2017-03-15 22:00:54 +00:00
mathvec
misc Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
nis Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
nptl Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
nptl_db Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
nscd Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
nss Fix build with --enable-static-nss [BZ #21088] 2017-03-15 13:32:23 -07:00
po
posix Fix test-errno issues 2017-03-15 17:05:34 -03:00
pwd
resolv Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
resource
rt One more obvious missing #include in the testsuite. 2017-02-19 10:29:34 -05:00
scripts build-many-glibcs: Remove no_isolate from SH config 2017-03-13 16:23:25 -03:00
setjmp
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soft-fp Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
stdio-common Narrowing the visibility of libc-internal.h even further. 2017-03-01 20:33:46 -05:00
stdlib Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
streams
string Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
sunrpc Remove the str(n)dup inlines from string/bits/string2.h. Although inlining 2017-03-13 18:45:42 +00:00
support support: Explain ignored failures of temporary file removal [BZ #21243] 2017-03-15 13:33:40 +01:00
sysdeps Improve float range reduction accuracy near pi/2 (bug 21094). 2017-03-15 22:00:54 +00:00
sysvipc
termios
time tzset: Clean up preprocessor macros min, max, sign 2017-03-07 17:45:39 +01:00
timezone
wcsmbs Split DIAG_* macros to new header libc-diag.h. 2017-02-25 09:59:46 -05:00
wctype
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BUGS
ChangeLog Improve float range reduction accuracy near pi/2 (bug 21094). 2017-03-15 22:00:54 +00:00
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config.h.in Rework -fno-omit-frame-pointer support on i386 2017-02-17 18:06:29 -02:00
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